Chatterjee Abhishek, Gupta Tejpal, Rangarajan Venkatesh, Purandare Nilendu, Kunder Shreya, Murthy Vedang, Budrukkar Ashwini, Ghosh-Laskar Sarbani, Agarwal JaiPrakash
Departments of Radiation Oncology.
Nuclear Medicine and Molecular Imaging, ACTREC/TMH, Tata Memorial Centre, Mumbai, India.
Nucl Med Commun. 2018 Sep;39(9):859-864. doi: 10.1097/MNM.0000000000000878.
The aim of this study was to identify the optimal timing of fluorine-18-fluoromisonidazole (F-MISO) PET/CT imaging to assess hypoxia in patients with head and neck squamous cell carcinoma.
Eighteen patients underwent pretreatment F-MISO PET/CT imaging after providing written informed consent. PET scans were acquired at 1, 3, and 5 h after injection of the radionuclide. The mean standardized uptake value (SUV) within a spherical region of interest placed on the contralateral neck musculature at the level of the largest tumor dimension was labeled as background. A value 1.5 times the background was deemed the threshold for significant hypoxia. Using this threshold, volumetric regions of interest encompassing the tumor were placed and hypoxic tumor volume (HTV) was generated for the primary tumor. Repeated-measures analysis of variance was used to compare the F-MISO PET/CT metrics across the three time-points. The volume of the primary tumor was also correlated with HTV.
The mean SUV of the background decreased consistently over time, resulting in increased focality of F-MISO uptake in the tumor tissues. Analysis of variance showed statistically significant differences in the mean SUV measurements of the background between the 1-h and the 3-h time-points (P=0.034) as well as the 1-h and the 5-h time-points (P=0.034). In parallel, the mean HTV increased from 1.72 cm at 1 h after injection to 6.52 cm at 3 h and further to 7.24 cm at 5 h, with a statistically significant difference between the 1-h and the 3-h scans (P=0.023) and the 1-h and the 5-h scans (P=0.023). There was a moderately good positive correlation between gross tumor volume on planning computed tompography (CT) and HTV at 3 h on the F-MISO scan (Pearson's correlation co-efficient 'r'=+0.753; P<0.0001).
The contrast resolution of F-MISO PET/CT scans in head and neck squamous cell carcinoma is suboptimal with early image acquisition, but improves significantly after delayed imaging. Increasing volume of tumor at the primary site is associated with an increase in hypoxia.
本研究旨在确定18F-氟米索硝唑（F-MISO）PET/CT成像评估头颈部鳞状细胞癌患者缺氧情况的最佳时机。
18例患者在签署书面知情同意书后接受了治疗前F-MISO PET/CT成像检查。在注射放射性核素后1、3和5小时进行PET扫描。将置于对侧颈部肌肉组织、最大肿瘤层面处的球形感兴趣区内的平均标准化摄取值（SUV）标记为背景值。背景值的1.5倍被视为显著缺氧的阈值。利用该阈值，放置包含肿瘤的体积感兴趣区，并生成原发肿瘤的缺氧肿瘤体积（HTV）。采用重复测量方差分析比较三个时间点的F-MISO PET/CT指标。原发肿瘤体积也与HTV相关。
背景的平均SUV随时间持续下降，导致肿瘤组织中F-MISO摄取的局灶性增加。方差分析显示，1小时和3小时时间点之间（P = 0.034）以及1小时和5小时时间点之间（P = 0.034）背景的平均SUV测量值存在统计学显著差异。同时，平均HTV从注射后1小时的1.72 cm增加到3小时的6.52 cm，并进一步增加到5小时的7.24 cm，1小时和3小时扫描之间（P = 0.023）以及1小时和5小时扫描之间（P = 0.023）存在统计学显著差异。计划计算机断层扫描（CT）上的肿瘤总体积与F-MISO扫描3小时时的HTV之间存在中度良好的正相关（Pearson相关系数“r”= +0.753；P < 0.0001）。
头颈部鳞状细胞癌中，早期图像采集时F-MISO PET/CT扫描的对比分辨率欠佳，但延迟成像后显著改善。原发部位肿瘤体积增加与缺氧增加相关。
